With the recent diversification of consumers' preferences, various types of alcoholic beverages have been produced. Among alcoholic beverages, wine is enjoyed by a wide range of generations, as well as beer, Japanese sake, and the like.
With the increased demand for wine, the areas where grape, which serves as a raw material of wine, is cultivated are extending from conventional warm areas to cool areas. As a result, the insufficient temperature during the cultivation period leads to an insufficient sugar content in the fruit, which necessitates chaptalization. However, there is such a problem that a wine chaptalized during its production is inferior in class to a non-chaptalized wine. For this reason, there are high demands for obtaining a wine which does not require the additional chaptalization during its production, and for obtaining a fruit of grape having a sugar content sufficient for a raw material of wine.
Noble rot wine and ice wine have been known as wines which are produced with the sugar content in the fruit of grape being increased.
Noble rot wine is a white wine made from a fruit of grape infected with a noble rot fungus called Botrytis cinerea. The noble rot fungus creates numerous holes on the skin of the fruit, and water in excess evaporates therethrough. Thus, the sugar content increases, which results in a very sweet wine with rich in aroma.
Regarding ice wine, the harvest time is delayed to winter, and the fruit of grape is frozen and thawed repeatedly several times in the climate. As a result, water in the fruit of grape gradually decreases, so that grape with a high sugar content is harvested. Hence, a sweet and aromatic wine can be produced.
Besides these methods, as a method for increasing a sugar content in a fruit using an agent, Patent Literature 1 describes a method in which a plant is grown, while a solution containing an iodine-cyclodextrin inclusion compound is sprayed to flowers or leaves of the plant.